"This was a savage and brutal attack targeting innocent festival-goers," he said. "I wish to express my heartfelt condolences and those of the Irish people to the families of the victims, those who were injured and to the people and the authorities of the United States on this tragic day."

Irish diplomats in the consulate general in San Francisco and the honorary consulate in Las Vegas are monitoring the situation.

The Department of Foreign Affairs issued a contact number for families in Ireland who have concerns about relatives to ring the consular assistance unit on +353 1 408 2527.